Add a protocol test for async originURL in DOMSnapshot.captureSnapshot

Change-Id: Id8943bd70fa5fd7df1e2d4b5b02bff7117e6cf44
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1832915
Commit-Queue: Johannes Henkel <johannes@chromium.org>
Reviewed-by: Johannes Henkel <johannes@chromium.org>
Cr-Commit-Position: refs/heads/master@{#703545}

third_party/blink/web_tests/inspector-protocol/dom-snapshot/captureSnapshot-origin-url-async-expected.txt

+Tests that DOMSnapshot.captureSnapshot records origin url of dom nodes generated by script.
+DIV: http://a.test/script.js
+

third_party/blink/web_tests/inspector-protocol/dom-snapshot/captureSnapshot-origin-url-async.js

+(async function(testRunner) {
+  var {page, session, dp} = await testRunner.startBlank('Tests that DOMSnapshot.captureSnapshot records origin url of dom nodes generated by script.');
+  await dp.DOMSnapshot.enable();
+  await dp.Runtime.enable();
+  const res = await dp.Runtime.setAsyncCallStackDepth({maxDepth: 10});
+
+  await session.evaluateAsync(`
+      setTimeout("document.body.appendChild(document.createElement('div'))", 0);
+      new Promise(fulfill => setTimeout(fulfill), 0);
+      \n//# sourceURL=http://a.test/script.js`);
+
+  const {result} = await dp.DOMSnapshot.captureSnapshot({'computedStyles': []});
+  function lookupRareString(table, index) {
+    const entryIndex = table.index.indexOf(index);
+    return entryIndex >= 0 ? result.strings[table.value[entryIndex]] : "";
+  }
+  const nodes = result.documents[0].nodes;
+  let nodeIndex = 0;
+  for (const nameIndex of nodes.nodeName) {
+    const name = result.strings[nameIndex];
+    if (name === 'DIV') {
+      const originURL = lookupRareString(nodes.originURL, nodeIndex);
+      testRunner.log(`${name}: ${originURL}`);
+    }
+    ++nodeIndex;
+  }
+  testRunner.completeTest();
+})
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